Communication apparatus

ABSTRACT

Communication apparatus in which an operator selects information items or characters which are visually displayed in groups sequentially. The operator observes the sequential display of the groups and selects the group containing the character he desires to communicate by operating a single switch mechanism in coincidence with the visual display of that group. The apparatus then sequentially displays the characters within the selected group. The operator then selects his desired character by operating the switch in coincidence with the display of that character.

,ijnited States atent [1 1 Watts et a1.

Nov. 6, 1973 COMMUNICATION APPARATUS lnventors: Eugene R. V. Watts, Wilton; Alfred J. Marcotte, Jr., Derry, both of NH.

Assignee: Sanders Associates Inc., Nashua,

3,696,395 10/1972 Barron 340/325 Primary Examiner-David L. Trafton AztorneyLouis Etlinger [57] ABSTRACT Communication apparatus in which an operator selects information items or characters which are visually displayed in groups sequentially. The operator observes the sequential display of the groups and selects the group containing the character he desires to communicate by operating a single switch mechanism in coincidence with the visual display of that group. The apparatus then sequentially displays the characters within the selected group. The operator then selects his desired character by operating the switch in coincidence with the display of that character.

13 Claims, 31 Drawing Figures J ZO A B E F /2e-2 c 0 G H J M N L SP OFF RECORDING DEVICE PATENTEDHBY 5 m5 SHEET 3 BF 6 L O mw Y FlGH COMMUNICATION APPARATUS BACKGROUND OF INVENTION 1. Field of Invention This invention relates to novel and improved communication apparatus and in particular to such apparatus in which each information item selected for communication is visually displayed.

Communication apparatus is useful for communication between one person and another or between a person and a machine, as for example, an electronic data processing machine.

2. Prior Art In the prior art, communication apparatus has been embodied in keyboard operated displays in which an operator selects information items or characters from a keyboard having a separate key for each character in the character repertoire. As each character is selected, it is displayed visually on a display screen, such as a cathode ray tube screen. This type of prior art communication device generally requires an operator with the physical ability to depress keys having different locations on the keyboard. For this reason, it is not generally of any use to handicapped personnel who have limited physical abilities, as for example, quadraphlegics, multiple sclerosis victims, cerebral palsy victims and many others.

One prior art communication device which is particularly adapted for use by handicapped personnel is described in U.S. Pat. No. 3,651,512. This device includes a display unit having a display panel with a series of compartments containing lamps. Translucent windows are located over the compartments and have messages or other similar information printed thereon. A switch unit, which in one case is hand held, having four switches allows an operator to turn the display panel on and off and to sequentially illuminate the lamps in either vertical or horizontal direction so as to select a desired message or item of information. Many handicapped personnel do not have the physical ability or power to operate or grasp the four switch control unit of this prior art device.

BRIEF SUMMARY OF INVENTION An object of the present invention is to provide novel and improved-communication apparatus.

Another object is to provide novel and improved communication apparatus that can be readily used by handicapped personnel.

Still another object is to provide communication apparatus that can be used by a handicapped individual who isunable to use his hands, or unable to speak, or is otherwise weak or ill.

Yet another object is to provide communication apparatus in which the operator can select information items through the operation of a single switch mechanism.

A further object is to provide novel and improved code responsive apparatus.

Briefly, communication apparatus embodying the invention includes a display screen for displaying the items in a set of information items, a manually operable switch, a display means and a control circuit. The display means includes a sequential group display means which is operable to sequentially display the items of the set a group at a time and further includes a sequential item display circuit which is operable to sequentially display the items of a selected group an item at a time. In the operation of the apparatus, the operator views the information items which are being sequentially displayed a group at a time. He selects a desired character by actuating the switch when the group containing that character is being displayed. The control means respond to the actuation of the switch at this time to initiate the operation of the sequential item display circuit which sequentially displays the information items within the selected group. The operator again actuates the switch when the desired item is visually displayed. The control circuit responds to the further actuation of the switch to interrupt the operation of the sequential item display circuit and to enter the selected information item into a storage device.

In accordance with one feature of the invention, the communication apparatus becomes operable only after a proper code orsequence of information items is selected by the operator. This feature is particularly attractive for use by voice operated switch users in that the user can carry on a conversation with other people without accidentally turning the communication apparatus on. This feature is embodied in code responsive apparatus which includes means for displaying during consecutive cycles a set of characters, one at a time, in sequence, a manually operable switch and a control circuit. The operator enters a predetermined code by actuating the switch in coincidence with the visual display of the characters of a predetermined code, a character at a time, in the order they appear in the code. The control circuit produces a control signal when the switch has been sequentially activated in coincidence with the visual display of all the characters of a predetermined code.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 6 is'a partial and exploded perspective view of I a single display element location of the visual communication apparatus shown on FIG. 1;

FIG. 7 is a block diagram of visual communication apparatus embodying the present invention;

FIG. 8 is a block diagram, in part, and a logic diagram, in part, of the keyboard control network, timing network and code scan network of the visual communication apparatus in FIG. 7;

FIG. 9 is a block diagram, in part, and a logic schematic diagram, in part, of the address counter select network of the visual communication apparatus of FIG. 7.

FIG. 10 is a block diagram, in part, and a logic schematic, in part, of the X and Y decoder and driver network of the visual communication apparatus shown in FIG. 7; and

DESCRIPTION OF THE PREFERRED EMBODIMENT It is contemplated that communication apparatus embodying the present invention may be employed to communicate various different items of information where an item may range from a single alphanumeric character or a punctuation symbol to a message comprised of several such characters arranged in conventional word form. However by way of example, and completeness of description, the communication apparatus embodying the invention is illustrated herein for the case where each of the information items in a set are different ones of a set of alphanumeric characters together with some special control items.

With reference now to FIG. 1, communication apparatus embodying the present invention is shown to include a display console 20 haying a display screen 23, a manually operable switch 21 and an output recording device 22. The manually operable switch may take on not only the illustrated hand held form but other forms such as foot operated, voice operated and other suitable forms. The recording device 22 may be any suitable type of recording device which makes record of characters received at its input such as a typewriter, printer, magnetic or paper tape recorder, cathode ray tube display and the like.

The display console 20 and display screen 23 may comprise any suitable display device such as a cathode ray tube, plasma display panel, X and Y addressable illuminating element array and the like. By way of example, the X and Y addressable illuminating element array has been chosen for the embodiment illustrated herein. Accordingly, the display screen 23 includes a plurality of compartments each containing an illuminating element and each having a translucent window which bears an alphanumeric character. This is best shown in the partial view of FIG. which illustrates the compartment for the alphanumeric character B. The letter B, which is imprinted upon the translucent window 25, is visible only when the associated illuminating element 24 within the compartment is illuminated.

Referring again to FIG. 1, the alphanumeric characters or the compartments to which the characters are assigned are divided into a number of groups 26-1 to 26-4. Each of the groups is shown to be further divided or subdivided into four subgroups. For convenience, only the characters in the group 26-2 (upper right hand quadrant) have been illustrated. Others of the alphanumeric characters and various other characters which are employed in standard character sets may be assigned to the character locations in the other three groups or quadrants.

The display console also includes an additional set 27 of dispaly compartments located below the display screen 23. This additional set of display compartments 27 is shown in FIG. 1 to bear the numerals 1 through 4 and a speedcontrol information item (SL). The set of characters 27 are part of the code responsive feature of the present invention which must be enabled to initiate operation of the visual communication apparatus.

Before describing the circuits of the display console and code responsive apparatus, the technique of selecting characters or how an operator uses the communication apparatus will be first described.

In the standby mode or condition of the visual communication apparatus none of the characters on the display screen 23 is illuminated. The characters in the code responsive set 27 are illuminated one at a time in sequence on a repetitive basis. The operator activates the communication apparatus by entering a predetermined character sequence or code. He does this by actuating the switch 21 in time coincidence with the visual display of the numeric characters in the set '27 during consecutive cycles. FIGS. 3A through 3D, 4A through 4D and 5A through 5D illustrate the entry of an exemplary code of 4 3 2. During the first sequential presentation of the numeric characters, the switch 21 is activated when the character 4 is visually displayed as shown in FIG. 3D. During the next sequential presentation of the characters, the switch is activated when the character 3 is displayed as shown in FIG. 4C. During the next ensuing character presentation, the switch is activated when the character 2 is displayed as shown in FIG.v 5B. When the code has bee-n thus correctly entered, the code, responsive apparatus contained within the display console 20 produces a control signal which enables the display console circuits.

Once enabled, the display console circuits are operable to sequentially illuminate the character groups 26-1, 26-2, 26-3 and 26-4 as shown in FIGS. 2A through 2D. In FIGS. 2A through 2D as well as FIGS. 2E through 2L, the sector which is illuminated is crosshatched. As an example, if the operator desires to select the letter D, he would activate the switch 21 when the sector 26-2 is illuminated as shown both in FIG. 1 and FIG. 2B. The subgroups 26-21, 26-22, 26-23 and 26-24 within groups 26-2 would then be sequentially illuminated as shown in FIGS. 2E through 2H. In order to select the letter D the operator would again actuate the switch 21 when the upper lefthand sector or quadrant 26-21 within the group 26-2 is illuminated as in FIG. 2E.

The A, B, C, D and E compartments in the subgroup or sector 26-21 would then be sequentially illuminated as shown in FIGS. 2I through 2L. The operator would then actuate the switch 21 when the letter D compartment is illuminated as in FIG. 2L.

If the operator has selected the wrong group or subgroup, the illuminating sequence will continue for two sequencing cycles and thenretum to the sequential illumination of the groups so long as theswitch 21 has not been actuated. In other words, if the operator makes an erroneous selection of a group or subgroup, he merely waits for the illumination sequence to revert from the subgroup sequencing to group sequencing.

Two items of information shown in group or quadrant 26-2 are for the purpose of providing control functions. Thus, the SP information item, if selected by the operator, causes the sequencing cycle to either speed up or slow down depending upon the speed of the sequencing cycle at the time the control item SP is selected. When the sequence cycle is operating at its slower rate, the speed control item SL in the additional display compartments 27 is illuminated. The OFF control item is selected by the operator when he wants to return the visual communication apparatus to its standby mode in which the code responsive display elements 27 are sequentially illuminated.

In the description which follows a number of circuit blocks shown in the drawing are discussed. These circuit blocks contain known circuits which are actuated by bi-level electrical signals applied thereto. When the signal is at one level, (say, the high level) it represents the binary digit 1 and when it is at the other level it represents the binary digit 0. Also, to simplify the discussion, rather than speaking of an electrical signal being applied to a block or logic state, it is sometimes stated that a l or a is applied to the block or stage.

The flip flop, shift register, counter, one-shot multivibrator, and logic gates or other blocks shown in the drawing may take on any suitable form. For example, these known circuits may be selected from any or all of the following catalogs: Fairchild Semiconductor Integrated Circuit Catalog, a catalog of Fairchild Semiconductor, lnc., Texas Instrument TTL Integrated Circuit Catalog, a catalog of Texas Instrument, lnc., and Signetics, 54 74 Handbook, a catalog of Signetics, Inc.

Coincidence gates are represented in the drawing with the conventional AND gate symbol having a dot therein and OR gates are represented by the conventional OR gate symbol with a ricontained therein. A

small circle at the output of these gates represents signal inversion such that the AND and OR gates becomes NAND and NOR gates, respectively. 'When a signal flow path contains more than a single lead or conductor, a slash mark is made through the path together with an adjacent number indicating the number of conductors in the path. One final note before proceeding with the description, the signal leads have in some cases been interrupted and labeled rather than shown as continuous leads so as to avoid cluttering in the drawing.

Referring now to FIG. 7, there is shown a block diagram of visual communication apparatus which embodies the present invention. The switch 21 is essentially a key type switch which provides an input signal INP to a timing network 30 and a keyboard control network 31. In its normal position the switch 21 is connected to a source of 0s 28 such that the input signal INP normally has a vlaue of 0. When the keying switch 21 is actuated, it is connected to a source of ls 29 so that the input signalINP has a value of l. The timing network 30 is arranged to provide a pair of clock signals 4;] and (1:2. i

The keyboard control network 31 responds to the input signal INP to provide either a code select pulse CS P to a code scan network 32 or a keyboard pulse KBDP to an address scan network 33. In the standby mode, the code scan network 32 is operative to sequentially scan the code characters 27. It is in this standby mode that the keyboard control network 31 provides the C81 code scan network 32. A two bit code representing the code characters (1, 2, 3, or 4), which are illuminated at the time the Cw signal is received, is coupled from the network 32 to the keyboard control network 31. When the appropriate code or character sequence has been entered by the operator, the keyboard control network ceases to supply CSP signals and commences to supply KBDP signals in response to further input INP signals. In addition, when the character sequence or code has been correctly entered, the keyboard control network 31 produces a keyboard on KBDON signal which is also applied to the address select network 33. The complement signal KBDON is employed to enable the code scan network during the standby mode and to disable it when the code has been correctly entered.

When enabled by the KBDON signal, the address scan network 33 provides a set of codes or binary numbers sequentially, one at a time, to an X and Y decoder and driver network 36. The network 36 decodes the binary numbers and in response thereto provides illumination drive signals to the appropriate groups and illumination elements of the dsiplay screen. For convenience, the visual communication apparatus circuits are being illustrated for the case where the display screen is comprised of 16 display element locations or one quadrant or group of the display screen 23 of FIG. 1. For this reason, the display screen has been labeled 26-2 in FIG. 7 and it will be assumed that the display characters or information items are the same as those shown for the display area 26-2 in FIG. 1. Accordingly, the networks 33 and 36 will be operative to sequentially illuminate the subgroup or sector areas 26-21, 26-22, 26-23 and 26-24 and, once a particular sector is selected, will be further operative to sequentially illuminate the characters within the selected sector.

The output of the address scan network is essentially a four bit code together with its four complement signals and two additional control signals as designated by I the numeral 10. The four code signal elements represent a character code CHC which is applied to a character register 37 at its data in D, input. The character code is loaded into the register 37 only when a character has been properly selected by the operator by means of a load signal CI-ILD applied to the LD input of register 37 from the address scan network 33. This code contained in register 37 together with a data valid signal also produced by network 33 can be applied to the recording device 22 (FIG. I).

The character code CI-IC is also applied to the keyboard control network 31 which reponds thereto to interpret the selection of either of the control functions SP or OFF. When the OFF function is selected by the operator, the keyboard control network disables the KBDON signal. When the SP (speed control) function is selected by the operator, the keyboard control network 31 responds by issuing a speed change SCH signal to the timing network 30. The timing network 30 responds to the SCH signal to either speed up or slow down the clock signal (I) and to control the illumination of the SL lamp in additional display compartments 27.

Referring next to FIG. 11, there is shown a typical illumination element or crosspoint of the matrix or array of illumination elements which make up the display screen 26-2. As shown in FIG. 11, the crosspoint is defined by the crossing of an X (row) and Y (column) conductor. Between each of these conductors at each crosspoint is connected a diode 39 and an illuminating element (a lamp) 40. When the decoder and driver networks 36 select an X and a Y conductor, a circuit will be completed between the selected X and Y conductors to provide current flow in the conventional sense through the lamp 40 causing it to illuminate.

Referring now to FIG. 8, the keyboard control network 31 is shown to include a pair of NAND gates 40 and 41 which respond to the input INP signal to produce either'the complement C S I of a CSP signal or the KBDP signal, respectively. When one of these gates is enabled the other is disabled and vice versa by a key board on/off D-type flip flop 43.

During the standby mode, the Q and O outputs of flip flop 43 are and 1, respectively, so as to enable gate 40 and disable gate 41. As the operator operates the switch 21 (FIG. 7) in the standby mode, each INP signal is passed by the enable gate 4 Q as a CSP signal to the code scan network 32. The CSP signal is also inverted by means of an inverter 45 so as to apply a CSP signal to the shift SH inputs of a pair of registers 46 and 47.

The code scan network 32 includes a scan counter 49 and a decoder and driver network 50 which when enabled by the KBDON signal responds to the count values of the counter 49 to sequentially illuminate the numeric characters 1, 2, 3, 4 of the additional display compartment set 27. The GSP signal is applied to the clear CL input of the scan counter 49 and the clock signal l is applied to the count input CP thereof. In the absence of an INP signal, the C SPsignal is a 1 whereby counter 49 responds to the clock signal (#1 to cycle through its count values. For the case of the illustrated embodiment of the code responsive apparatus where only four code elements are to be scanned, the counter 49 may simply be a two bit counter such that there are four count values to be cycled through. The decoder and driver network 50 responds to the sequential presentation of these count values to decode and sequentially illuminate the numeric characters 1 through 4 of the additional character set 27. To this end, the decoder may simply comprise a set of four NAND gates approximately connected to the outputs of counter 49 (including the ls complements of these outputs) with each NAND gate being enabled by the KBDON signal. That is, the scan counter 49 is enabled at all times to cycle through its count value, but the decoder 50 responds to the count values only during the standby mode to sequentially illuminate the code elements 1 through 4. When a 6% signal is produced in response to an INP signal (actuation of the key type switch 21), the counter 49 is cleared and begins to cycle through its count values anew.

The bits of the count outputs of the scan counter 49 are applied to the data in D, inputs of a pair of registers 46 and 47. The GSP signal is inverted by means ofan inverter 45 so as to apply a CSP signal to the shift SI-I input of these registers. In operation then the count value of the scan counter 49 which exists at the time a signal is generated, is shifted into the registers 46 and 47 with one bit occupying the first bit position of register 46 and the other bit occupying the first bit position of register 47. On the next two ensuing GSP signals, two more count values are similarly shifted into the registers 46 and 47. Assuming that the three count values now stored in the registers 46 and 47 do indeed represent the correct code, a code combination decoder 48 responds thereto to produce a l to 0 transition at its output. This I to 0 transition is applied to the clear input of flip flop 43 whereby flip flop 43 changes state. This disables the decoder and driver network 50, clears the registers 46 and 47, disables NAND gate 40 and enables NAND gate 41. The KBDON signal now becomes a 1 so as to enable the address scan network (FIGS. 7 and 9) to cause the character code CI-IC to change from the OFF value. The keyboard OFF decoder 44 in FIG. 8 responds thereto to produce a l at the D input of flp flop 43. Accordingly, flip flop 43 will remain in this state, until the operator again selects the OFF control function. When this does happen, the decoder 44 will apply a zero to the D input of flip flop 43 and KDBP signal generated by the INP signal produced by this selection will cause the flip flop 43 to change its state. The keyboard control network is then returned to the standby mode of operation.

The design of the code combination decoder 48 is, of course, a function of the code to which the code responsive apparatus will respond. For example, for a code consisting of three consecutive count values of 11, the code combination decoder may suitably comprise a set of gates which performs a six input AND function with signal inversion (a six input NAND function) to produce a l to 0 transition when the third count value of 11 is selected by the operator.

The keyboard control network 31 is shown to further include a speed change decoder 60 which receives the character code CHC from the counters 34 and 35 (FIG. 7) to detect the code representing a speed change SP selection by the operator, and to produce a speed change signal SCH. Since this code is generated once per scan cycle when sub-group 26-24 has been selected (see FIG. 1), the speedchange decoder is enabled by the KDBP pulse only when the operator selects the SP speed change items. The decoders 44 and 60 may comprise any suitable gating function for the codes assigned to the OFF and SP functions. For example, if the codes are l l l l and l 101, each decoder can take the simple form of a four input NAND gate with the complement of the 0 bit position being employed. In addition, the output of the SP decoding gate would be further gated with the KBDP signal via an AND gate.

Still referring to FIG. 8, the timing network is shown to include a one shot multivibrator 51 which is connected as a gated pulse generator to produce a sequence of pulses until interrupted by the input INP signal. To this end, the INP signal is inverted by means of an inverter 52 so as to normally enable a NAND gate 53 to pass the pulse sequence from the O output of one shot 51 to its input. When the INP signal becomes a l, gate 53 becomes diabled so as to interrupt the pulse sequence produced by one shot 51.

A pair of one bit counters 54 and 55 serve to divide the frequency of the pulse sequence. Both of these counters are employed during the slow operating mode and only one of these counters, 55, is employed during the fast operating mode. A speed control flip flop 59 and a set of steering gates 56 through 58 serve to control whether just counter 55 or both counters 54 and 55 will be employed to divide the frequency of the pulse sequence produced by one shot 51. To this end, flip flip 59 is connected as a one bit counter with its 6 output being applied to its D input. The clock input CP is connected to the speed change signal SCI-I produced by the speed change decoder 60 in the keyboard control network 31.

For the fast mode of operation, flip flop 59 is in the state where its Q and O outputs are 0 and 1, respectively. This causes gate 56 to be disabled so as to apply a l to the input of gate 58 and gate 57 to be enabled to pass the output of counter 54 to the other input of gate 58. The output of gate 58 then drives the count input of the counter 55. On the other hand in the slower operating mode, the Q and O outputs of flip flop 59 are l and 0, respectively. This causes gate 57 to be disabled so as to apply a l to one input of gate 58. Gate 56 is enabled so as to pass the pulse sequence from the Q output of one shot 51 to the other input of gate 58. Accordingly, in the faster operating mode only the counter 55 is connected to divide the frequency of the pulse sequence.

The clock signal (#2 is taken from the output of the gate 58. The clock signal (1)] is taken from the output of an AND gate 62 which gates the Q output of counter 55 with the Q output of a flip flop 61. The flip flop 61 serves to double the normal key or quadrant dwell time after each actuating switch depression. This feature is desirable in order to avoid confusion of the operator when the keyboard recycles to the first quadrant, subquadrant or key. This gives the operator an opportunity to view his selection before the next cycling sequence in the selection process takes place. To accomplish this, flip flop 61 has its D input connected to a source of l s and its clock input CP connected to the Q output of counter 55. The complements of the INP signal (taken from the output of inverter 52) serves to clear counters 54 and 55 as well as flip flop 61 whenever the INP signal has a to 1 transition. This cause the Q output of flip flop 61 to be a 0 and the Q and Q outputs of counter 55 to be 0 and 1, respectively. Upon the occurrence of the next 2 signal, the one bit counter 55 will change its state such that its Q and Q outputs become I and 0, respectively. Flip flop 61 does not change state at this time such that gate 62 is disabled by the 0 from the Q output of flip flop 61 so that no (111 clock pulse is produced. When the (62 signal again occurs, the counter 55 will change its state such thatits Q and Q outputs become 0 and l, respectively. This will cause flip flop 61 to change its state so that its Q output becomes a l to enable the gate 62. For all subsequent 52 pulses in the absence of another INP signal, the flip flop 61 does not change state such that the gate 62 is enabled to pass the pulse sequence occurring at the Q output of the counter 55 as the clock signal sequence l.

With reference now to FIG. 9, the address scan network 33 includes a pair of AND gates 67 and 68 which, when enabled by the 'KBDON signal, steer the clock signal l to a selected one of a number of counters, namely, a group counter 34 and a subgroup counter 35 depending upon the stage in the character selection process to which the operator has progressed. The outputs of the counter 34 and 35 together with the outputs of a counter select flip flop 66 constitute the ten signal elements previously referred to as being applied to the X and Y decoder 36 (FIG.

During the standby mode of operation, the counters 34 and 35 are cleared to the all Os state and the KBDON signal is a 0 such that AND gates 67 and 68 are disabled from coupling the 1 clock signal to either of the counters. The counter select flip flop 66 isin the state where its Q and Q ouptuts are 0 and 1, respectively. When the operator has entered the correct code, the KBDON signal becomes a 1. This fully enables gate 68 to pass the 11:1 clock signal to the group counter 34. The group counter 34 begins to cycle through its four count values which are interpreted by the decoder network 36 so as to sequentially illuminate the quadrants 26-21 through 26-24 (FIGS. 1 and 7).

When the operator selects a quadrant; a KBDP pulse will be generated. Thecomplement KBDP is applied as one input of a NAND gate' 65. NAND gate 65 is enabled at this time by the output of an override counter 38 (which is described below). This will produce a 0 to 1 transition at the output of gate 65 which is applied to the CP clock input of flip flop 66. Flip flop 66 then switches so that its Q and Q outputs become 1 and 0, respectively. AND gate 68 becomes disabled and AND gate 67 is now fully enabled to steer the clock signals 1 to the CP clock input of the subgroup counter 35.

The subgroup counter 35 now begins to cycle through its four count values which are interpreted by the X and Y decoder network 36 to sequentially illuminate the characters within the selected quadrant as determined by the count value of group counter 34. The lower order bit (D) of the subgroup counter 35 is applied to the override counter 38. The purpose of the override counter 38 is as follows. If the operator discovers that his selection of the quadrant or group is erroneous, he does not actuate the switch 21. The override counter 38 then counts through two sequencing cycles of the subgroup counter 35 to produce a l to 0 transition at its output. This I to 0 transition causes the output of NAND gate 65 to produce a 0 to 1 transition to thereby switch flip flop 66 to the state where its Q and Q output are 0 and 1, respectively. As described above, this state of flip flop 66 selects group counter 34 to receive the clock signals qbl whereby the character selection process begins anew with the quadrants 26-21 through 26-24 being sequentially illuminated. The operator may now make a correct selection.

Returning now to the point in the character selection process where the operator has made a correct selection of a quadrant, the subgroup counter 35 begins to cycle through its count value. When the operator properly selects a character (within two cycles of counter 35) a KBDP pulse will be generated. A NAND gate 69 is enabled by the l at the Q output of flip flop 66 to pass the KBDP pulse to the clear CL inputs of counters 34 and 35. This causes counters 34 and 35 to return to the all Os count value. The KBDP pulse will be passed by NAND gate 65 to produce a 0 to 1 transition at its output. This causes flip flop 66 to change state such that its Q and Q outputs become 0 and l, respectively. The 1 to 0 transition at the Q output of flip flop 66 causes the override counter 38 to become cleared to its all Os state. However, the override counter output which is applied to AND gate 65 is the complement of its second stage and is a l at this time. i

The address scan network is now in condition for the character selection process to begin anew so that the operator can select another character. When it is desired to turn the visual communication apparatus off, the operator first selects the quadrant 26-24 and then selects the OFF control function while the subgroup counter 35 is cycling. This will cause the keyboard control network to produce a KBDP pulse. The OFF code is detected by the KBD OFF decoder 44 (FIG. 8) so as to cause flip flop 43 to switch and thereby cause the KBDON signal to become a O. This disables AND gate 67 and 68 in FIG. 9. The KBDP pulse is passed by NAND gate 69 to clear the counters 34 and 35 to their all Os count value. The KBDP pulse is passed by NAND gate 65 to cause flip flop 66 to change to its state where its Q and Q outputs are 0 and 1, respectively. The l to 0 transition at the output of flip flop 66 causes the override counter 38 to clear. The address scan network has now been returned to its standby mode. 1 i

As described above whenthe character selection process is at the point where the operator has selected a quadrant and is about to select a character, the Q output of flip flop 66 is a 1. This enables a NAND gate 70. When the operator does make a character selection at this time, a KBDP pulse is generated which is passed by NAND gate 70 as a l to transition to the clear input of a flip flop 71. The flip flop 71 has its D input connected to a source of 1s and its-clock input CP connected to receive the 2 clock pulse sequence. The l to 0 transition at its clear input at this time causes flip flop 71 to become cleared to the state where its Q and Q outputs are 0 and 1, respectively. The O to l transition at the 6 output of flip flop 71 is the character load CHLD signal which causes the character code at the output of counters 34 and 35 to be loaded into the character register 37 (FIG. 7). On the next ensuing 2 clock pulse, the flip flop 71 will switch back to the state where its Q and Q outputs are l and 0, respectively. The 0 to 1 transition at the Q output of flip flop 71 is the data valid signal which signals the recording device that the data contained in character register 37 is valid. The flip flop 71 will remain in this state until NAND gate 70 produces another 1 to 0 transition (at the time the operator makes another character selection).

Referring to FIG. 10, the X and Y decoder network 36 is shown to include an X decoder and a Y decoder. The circuit elements and connections therebetween are substantially identical and corresponding circuit elements have been given identical reference numerals followed by either an X or a Y to identify to which decoder it belongs. There is one exception, however. The signal elements A, A, C and C applied to circuit elements in the Y decoder are replaced with the signal elements B, B, D and D respectively, in the X decoder for the corresponding circuit elements.

When the group counter 34 (FIG. 9) is cycling, the Q and Q outputs of flip flop 66 (designated as FF66Q and FF66Q, respectively in FIG. 10) are 0 and 1, respectively. This selects a pair of NAND gates 75Y and 76Y in the Y decoder and a pair of NAND gates 75X and 76X in the X decoder which test the A and B output, respectively, of the group counter. A number of gates 81Y through 84Y and 81X through 84X are arranged in pairs to monitor thechanges in signal condition at the outputs of the gates 75Y, 76Y, 75X and 76X. Thus, gates 81Y and 82Y both receive the output of gate 75Y, gates 83Y and 84Y receive the output of gate 76Y, and so on. The outputs of gates 81Y and 82Y are connected via line drivers 85Y and 86Y to the two left hand columns of the array 26-2 (FIG. 7). The outputs of gates 83Y and 84Y are connected via line drivers 87Y and 88Y to the two right hand columns of the display array. The outputs of gates 81X and 82X are connected via line drivers 85X and 86X to-the top two rows of the display array. Finally, the outputs of gates 83X and 84X are coupled via line drivers 87X and 88X to the bottom two rows of the display array.

During the time that the group counter is cycling, the gates 81Y through 84Y and 81X through 84X are enabled by the outputs of another set of gates 77Y through 80Y, 77X through 80X, respectively. This is so since eachpf these gates has as an input FF66Q which is a 0 at this time. Accordingly, whenever the output of one of the gates 75Y, 76Y, 75X or 76X goes to 0, the outputs of its associated gate pair will become a 1. For example, when counter 34 is in its all Os state (A=0, B=0), the outputs of gates 75Y and 75X will be 0s and the outputs of gate 76Y and 76X will be l s. This causes the outputs of gates 81Y, 82Y, 81X and 82X to be all ls to thereby select the upper left hand quadrant of the display array 26-2 as defined by the two left hand columns in the two top rows. For the next count value of 10 (A l, B O), the outputs ofgates 76Y and X will be 0s and the outputs of gates 75Y and 76X will be ls. This causes the outputs of gates 83Y, 84Y, 81X and 82X to be all ls thereby selecting the upper right hand quadrant as defined by the two right hand columns in the two top rows. For the next two count values 01 and 11, the decoder is operative in a similar manner to select the lower left and right hand quadrants, respectively.

When a particular quadrant has been selected by the operator, the flip flop 66 changes state, such that FF66Q and FF66Q become 1 and 0, respectively. The subgroup counter 35 then begins to cycle. Gates 77Y to Y and 77X to 80X are all enabled by the 1 value of FF66Q. The output of gates 77Y to 80Y and 77X to 80X are monitored by gates 81Y to 84Y and 81X to 84X, respectively, since these latter gates are all enabled by the ls at the outputs of the corresponding gates 75Y, 76Y, 75X and 76X which are disabled by the 0 value of FF66Q.

As an example, suppose that the operator has selected the upper right hand quadrant. Since A 1 and B O for this case, only gates 79Y, 80Y, 77X and 78X will be enabled to monitor the C and D outputs of the subgroup counter 35. For the subgroup count value of 00 (C 0, D O), the outputs of gates 79Y and 77X are Os. This causes the outputs of the associated gates 83Y and 81Xto be ls to thereby select for illumination the upper left hand character (E in FIG. 1) of the selected upper right hand quadrant sector. For the subgroup count values of l0 (C l, D 0), the outputs of gates 80Y and 77X are Os. This causes the outputs of the corresponding gates 84Y and 81X to be ls so as to select for illumination the upper right hand character (F) in the selected upper right hand quadrant. For the next two subgroup count values of O1 and 11 the decoder is operative in a similar manner to select the lower left (G) and right (H) hand characters, respectively, in the selected upper right hand quadrant. For other selected quadrants the operation'of the subgroup cycling is similar with the gates which monitor the C and D outputs of the subgroup counter being determined by the count value A and B of the group counter.

What is claimed is:

1. Communication apparatus comprising:

a manually operable switch;

display means including a. sequential group display means for sequentially displaying the items of a set of information items a group at a time, and

b. sequential time display means for sequentially displaying the items of a selected group an item at a time; and

a control network including a. means for initiating the operation of said sequential group display means,

b. means responsive to the actuation of said switch during the visual display of a selected one of the groups to initiate the operation of the sequential item display-means so as to sequentially display the information items within the selected group, and

c. means responsive to a further actuation of the switch during the visual display of a selected one of the information items to interrupt the operation of the sequential item display means. 2. Communication apparatus as set forth in claim 1 wherein said sequential group display means and said sequential item display means both operate on a cyclic basis; and

wherein said control network further includes an override means which interrupts the operation of said sequential item display means in the absence of an actuation of said switch during a predetermined number of sequential item display cycles.

3. Communication apparatus as set forth in claim 1 wherein said display means further includes a display screen upon which said items are displayed sequentially either a group or an item at a time by said sequential group and item display means, respectively, at addressable locations thereon;

wherein said sequential group and item display means include a group and item counter, respectively;

wherein said control network further includes a timing generator which produces a clock pulse sequence; means responsive to each switch actuation to produce a i switch pulse; and

a steering control network responsive to said switch pulses to alternately enable said sequential group initiating means and said sequential item initiating means to steer said clock pulse sequence to said group and item counters; respectively, which respond thereto to sequentially generate the addresses of each group of each item within a selected group, respectively. 4. Communication apparatus as set forth in claim 3 wherein said interrupt means responds to the switch pulse produced by said further switch actuation to clear both of said counters. 5. Communication apparatus as set forth in claim 4 wherein said timing generator includes means for interrupting the generation of said clock pulse sequence for the duration of each said switch pulse. 6. Communication apparatus as set forth in claim 5 wherein said timing generator further includes means for delaying the generation of said clock pulse sequence after each switch pulse. 7. Communication apparatus as set forth in claim 6 wherein said control network further includes means responsive to the selection of one of said information items to disable said switch pulse producing means and said group and item initiating means. 8. Communication apparatus as set forth in claim 7 and further including means for displaying an additional set of symbols one at a time in sequence during consecutive cycles whenever said group and item initiating means are disabled; and

means for producing a control signal, whenever said switch has been sequentially activated in coincidence with the visual display of the symbols of a predetermined code; and wherein said disabling means responds to said control signal to enable said switch pulse producing means and said group and item initiating means. 9. Communication apparatus as set forth in claim 8 wherein said-control network further includes further means responsive to the selection of a further one of said information items to produce a speed control signal; and

wherein said timing generating means responds to said speed control signal to change the frequency of said clock pulse sequence.

10. Communication apparatus asset forth in claim 9 wherein said display screen comprises a plurality of compartments each containing an illuminating element and each having a translucent window bearing an information item which is visible when the illuminating element is illuminated, said compartments being arranged in rows and columns; and

wherein said group and item addressing means addresses said compartments by rows and columns.

11. Code responsive apparatus comprising:

means for displaying during consecutive cycles a set of characters one ata time in sequence;

a manually operable switch; and

a control circuit for producing a control signal whenever said switch has been sequentially activated in coincidence with the visual display of the characters of a predetermined code.

12. Code responsive apparatus as set forth in claim wherein said display means includes a display screen upon which said characters are displayed at addressable locations; and

address generating means which generates the addresses of said characters one at a time in sequence on a cyclic basis.

13. Code responsive apparatus as set forth in claim wherein said control circuit includes storage means for storing the addresses of the characters which coincide in time with the actuation of said switch;

and means for producing said control signal when said stored addresses correspond to the characters of the predetermined code.

mg UNITED STATES PATENT OFFICE A CERTIFICATE OF CORRECTION Patent No, 3, 771, 156 D ated Novembei' 6, 1973 Inventor(s) Eugene R. V. Watts, et a1 It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 12', Line 56 Claim 1 change "time" to -.-item--.

Signed and sealed this 161m day of July 1974.

( A Attest:

McCOY M; GIBSON, JR. c. MARSHALL DANN 'Attesting Officer 1 Commissioner of Patents 

1. Communication apparatus comprising: a manually operable switch; display means including a. sequential group display means for sequentially displaying the items of a set of information items a group at a time, and b. sequential time display means for sequentially displaying the items of a selected group an item at a time; and a control network including a. means for initiating the operation of said sequential group display means, b. means responsive to the actuation of said switch during the visual display of a selected one of the groups to initiate the operation of the sequential item display means so as to sequentially display the information items within the selected group, and c. means responsive to a further actuation of the swItch during the visual display of a selected one of the information items to interrupt the operation of the sequential item display means.
 2. Communication apparatus as set forth in claim 1 wherein said sequential group display means and said sequential item display means both operate on a cyclic basis; and wherein said control network further includes an override means which interrupts the operation of said sequential item display means in the absence of an actuation of said switch during a predetermined number of sequential item display cycles.
 3. Communication apparatus as set forth in claim 1 wherein said display means further includes a display screen upon which said items are displayed sequentially either a group or an item at a time by said sequential group and item display means, respectively, at addressable locations thereon; wherein said sequential group and item display means include a group and item counter, respectively; wherein said control network further includes a timing generator which produces a clock pulse sequence; means responsive to each switch actuation to produce a switch pulse; and a steering control network responsive to said switch pulses to alternately enable said sequential group initiating means and said sequential item initiating means to steer said clock pulse sequence to said group and item counters; respectively, which respond thereto to sequentially generate the addresses of each group of each item within a selected group, respectively.
 4. Communication apparatus as set forth in claim 3 wherein said interrupt means responds to the switch pulse produced by said further switch actuation to clear both of said counters.
 5. Communication apparatus as set forth in claim 4 wherein said timing generator includes means for interrupting the generation of said clock pulse sequence for the duration of each said switch pulse.
 6. Communication apparatus as set forth in claim 5 wherein said timing generator further includes means for delaying the generation of said clock pulse sequence after each switch pulse.
 7. Communication apparatus as set forth in claim 6 wherein said control network further includes means responsive to the selection of one of said information items to disable said switch pulse producing means and said group and item initiating means.
 8. Communication apparatus as set forth in claim 7 and further including means for displaying an additional set of symbols one at a time in sequence during consecutive cycles whenever said group and item initiating means are disabled; and means for producing a control signal, whenever said switch has been sequentially activated in coincidence with the visual display of the symbols of a predetermined code; and wherein said disabling means responds to said control signal to enable said switch pulse producing means and said group and item initiating means.
 9. Communication apparatus as set forth in claim 8 wherein said control network further includes further means responsive to the selection of a further one of said information items to produce a speed control signal; and wherein said timing generating means responds to said speed control signal to change the frequency of said clock pulse sequence.
 10. Communication apparatus as set forth in claim 9 wherein said display screen comprises a plurality of compartments each containing an illuminating element and each having a translucent window bearing an information item which is visible when the illuminating element is illuminated, said compartments being arranged in rows and columns; and wherein said group and item addressing means addresses said compartments by rows and columns.
 11. Code responsive apparatus comprising: means for displaying during consecutive cycles a set of characters one at a time in sequence; a manually operable switch; and a control circuit for producing a control signal whenever said switch has been sEquentially activated in coincidence with the visual display of the characters of a predetermined code.
 12. Code responsive apparatus as set forth in claim 11 wherein said display means includes a display screen upon which said characters are displayed at addressable locations; and address generating means which generates the addresses of said characters one at a time in sequence on a cyclic basis.
 13. Code responsive apparatus as set forth in claim 12 wherein said control circuit includes storage means for storing the addresses of the characters which coincide in time with the actuation of said switch; and means for producing said control signal when said stored addresses correspond to the characters of the predetermined code. 